Joint tenant
Both names on the agreement. You hold rights in the property, and you are also jointly liable for the full rent — if the other person stops paying, the landlord can look to you.
Named occupant
The tenancy stays in one name, but the agreement or a landlord letter records that you live there. Weaker than joint tenancy, but far better than nothing when a dispute starts.
Unrecorded sharer
No document mentions you. You depend entirely on the goodwill of the tenant, and you may have no claim on the deposit you contributed.
Whichever applies, write your own agreement
- Amounts paid by each person, and to whom.
- How and when a contributed deposit is returned.
- Notice each of you must give before leaving.
- What happens to the room if one person leaves mid-term.
General information, not legal advice. For a large deposit or a long term, have a lawyer look at the wording.