A user can choose only the branches they are mapped to. Check that the company is branch based, that the branch is active, that the user is mapped to it, and that the user signed in again.
Without it there are no branches to choose: no Branch tab, no Switch branch, and the Branch box on a user is switched off (Branches).
2
Is the branch active?
Where
Company setting > Branch > the branch's Status
What changes
An inactive branch is not offered by Switch branch and cannot be given to a user on the mapping screen. A user whose default branch is inactive cannot sign in at all.
It shows only when the company is branch basedand the user is mapped to at least two active branches. A user with one branch has nothing to switch to (Work in another branch).
"I am in the right branch but cannot make a document"
Do I tick the user's default branch again under More branches?
No. The default branch is always one of the user's branches. More branches is only for the extra ones.
I cleared a person on the branch mapping screen and they lost the branch.
Saving makes the ticked list the whole list for that branch. Open the screen, choose the branch, tick the person again and save (Map several users to a role or to a branch).