Give a tenant a way to reach you, report problems and see their rent.
Inviting a tenant gives them a way to reach you, and gives you their side of the record.
It happens on the property's Tenancy tab: + Add tenant records a new tenant — that alone contacts nobody — and Manage on a tenant opens their access.

There are two ways a tenant reaches you, and you can offer either or both.
The tenant portal goes to their email — they set a password, then see their rent, their documents, and a way to report a problem.
WhatsApp goes to their phone — no sign-in, no app, and most tenants answer faster on it; Send WhatsApp invite sends the opt-in.
It is the same conversation and the same record whichever they use. The panel also tracks each occupant's Right to Rent check.