You do not need to provide your address and it will not appear on the envelope automatically. That is one of the core features of the service.
When InmateAid sends a letter on your behalf, the return address on the envelope is InmateAid's address in Florida. Your name appears at the top, but the address below it is the company's, not yours. The inmate knows the letter is from you, but anyone else handling that envelope, including facility staff, sees only InmateAid's Florida address.
If you want your inmate to have your home address, you can include it inside the letter itself. That way you are making a deliberate choice to share it rather than having it printed on the outside of an envelope passing through a prison mailroom.
Most people prefer keeping their address off the envelope entirely, and for good reason. Mail in correctional facilities gets handled by multiple people before it reaches the inmate, and there are situations where having your home address visible creates concerns you simply do not need. The privacy protection is built in by default.