@Ana24181 I added a BBQ at the beginning of Corona, and I would also caution you to remember to clean it before guests arrive (or make sure your cleaner does). Nothing grosser than going to cook and finding a filthy grill.
I would recommend propane or natural gas. It requires the least amount of skill for the guests to use, and there are no hot coals that the guest can cause damage with. People can do A LOT of damage with hot coals, and people tend to underestimate how long they need to cool down before they can be safely disposed.
A few recommendations (based on my experiences):
Come up with rules and post them in your manual and on or near the grill. My guests have laughed at mine (I tried to make them funny) but they're all based on actual things guests have done.
First thing: ask guests not to cook things like beer can chicken, brisket, etc. It makes an unholy mess that can take ages to clean up, and the residue will attract pests. Running the barbeque for a long time also uses up lots of gas.
Remind them to turn the gas off at the wall or the bottle when they're done.
Choose a specific place for the grill that's not right against the house. Tell them not to move it. Chain it in place, if needed.