Renting out bedrooms, lease or other type of agreement?

[Nicholas J Robichaud]

I recently purchased a three family home in Pelham NH. I’m living in one of the units right now and am trying to rent out the other two bedrooms I have in my unit. I have tenants lined up now I just need to know if I need to have them sign a lease or if there’s a different kind of agreement for renting rooms? Any information would be appreciated, thanks!