Users with Admin/ Farm Owner permissions are able to manage who is invited and removed from farm accounts.
Instructions for inviting team members can be found here.
Click settings cog in top right of your screen
Click on the 'Team' tab
Click the red cross next to the user you would like to remove access from
To confirm you would like to delete this user, click the red 'REMOVE' button
Go to the hambuger menu by tapping the three white lines in the top left of your screen
Tap on 'Team'
Click on the grey circle with a '-' next to the user you would like to remove from your farm
Tap 'Delete User' then 'Remove'
You will see a confirmation showing the user has been removed from your farm