How to Add Someone to a Slack Channel on Desktop or Mobile

A new hire starts on Monday, a freelancer joins your launch, or a colleague needs to see the client conversation you've been having all week. Adding them to the right Slack channel takes a few clicks, and it saves you forwarding screenshots and repeating yourself.

The thing to know up front is that adding someone to a channel only works for people already in your Slack workspace. Anyone outside your company needs a different route. I'll cover both, following Slack's help centre, plus what to do when the person you want won't show up in the search.

Adding someone to a Slack channel on desktop

Slack's steps for the desktop app and Slack in a browser:

1. Open the channel you want to add someone to.
2. Click the member icon in the top right of the channel. It shows the faces or count of people already in it.
3. Click Add people.
4. Search by name, email address or user group.
5. Select the people you want.
6. Click Add.

Once you've added them, the channel shows up in their sidebar.

Adding someone to a Slack channel on your phone

On the Slack mobile app, Slack's help gives this route:

1. Open the channel.
2. Tap the channel name at the top of the screen.
3. Tap Add.
4. Select the people you want to add.
5. Tap Add to confirm.

It's handy for those moments when someone asks to be looped in while you're away from your desk.

Adding lots of people to a Slack channel at once

Setting up a new project channel for a whole department? You don't need to add people one by one. Slack's help says you can add up to 1,000 people to a channel at once. Searching by user group is the quickest way if your workspace has groups set up, such as a marketing or sales group, because one selection pulls everyone in.

If you're pasting in a list of email addresses, Slack points out one catch: if email addresses are hidden in member profiles in your workspace, you can't add people by email. Search by their names instead.

Who can add people to a Slack channel

Slack says all members and Multi-Channel Guests can use the Add people feature. So in most workspaces, you don't need to be an admin to bring a colleague into a channel you're in.

If you can't see the option, your workspace may have been set up differently, so check with your workspace owner or admin.

Adding someone outside your company to a Slack channel

This is where people get stuck, because a client or freelancer isn't in your workspace, so they won't come up in the search. Slack's help says that to add people from outside your company, you use Slack Connect to invite them to a channel.

Slack Connect links your channel to the other person's own Slack, so both sides can talk in one shared space. It suits ongoing client work well. If you only need someone for a short stint, your workspace owner may prefer to invite them as a guest instead, depending on how your workspace is managed.

Who you're adding	Route Slack's help describes
A colleague already in your workspace	Add people in the channel
A whole team or department	Add people, then search by user group
A client or partner at another company	Invite them through Slack Connect

Before you add someone to a Slack channel

In most channels, new members can scroll back through what's already been said, so it's worth a quick check before you hit Add:

• Scroll up and make sure nothing in the history is confidential to the people already there.
• Pin the key links or brief so the new person can catch up fast.
• Post a short welcome so they know why they've been added and what you need from them.

That welcome line matters more than people think. A newcomer added to a busy channel without context usually just mutes it.

Choosing the right Slack channel for new people

For small teams, I'd keep channel additions deliberate. Adding someone to every channel on day one buries them in noise. Start with three or four: an announcements channel, their team channel and the project they're working on. Let them join the rest when they need them.

The same thinking applies to group chats in other apps. If you're comparing, my guide to adding someone to a WhatsApp group covers the equivalent steps, and for community servers there's how to add friends on Discord.

If you can't add someone to a Slack channel

1. Check they're already a member of your workspace. If not, invite them to the workspace first or use Slack Connect.
2. Try searching by their name rather than their email, in case emails are hidden in profiles.
3. Make sure you're adding fewer than 1,000 people in one go.
4. If you're a guest with access to a single channel, you may not have the option at all.
5. Ask your workspace owner or admin if the Add people button is missing.

Frequently asked questions

How do I add someone to a Slack channel?

Open the channel, click the member icon in the top right, click Add people, search by name, email or user group, then click Add.

How do I add someone to a Slack channel on mobile?

Open the channel, tap the channel name at the top, tap Add, select the people and tap Add again.

Can I add someone from another company to my Slack channel?

Not with Add people. Slack's help says people from outside your company are invited to a channel through Slack Connect.

How many people can I add to a Slack channel at once?

Slack says you can add up to 1,000 people to a channel at once.

Why can't I add someone by email in Slack?

Slack says that if email addresses are hidden in member profiles, you can't add people by email. Search by their name instead.