Go to Settings, then the team section, and choose Invite by Email. Enter the person's email and they will get an invitation to join your account.
This is how you add an agent, an assistant, a transaction coordinator, or anyone else who works on your listings. They get their own login rather than sharing yours.
How many people you can add depends on your plan. If you are at your limit, upgrading raises it.
To remove someone, open the same team section and remove them there. They lose access immediately, and the work they created stays in the account.
Only the account owner can invite or remove people.