how do you say..

how do you say "please take a seat" in Japanese?
for example, in the clinic, the nurse asks the patient to take a seat before the patient's turn to see the doctor.

and how do you ask for someone's home address in Japanese?

Thanks.

Please have a seat and wait (for your turn).

どうぞ座ってお待ちください。(douzo suwatte omachi kudasai)

What's your address: 住所は何ですか？

Assuming once again a situation at a clinic, asking for home address would be:
- Go-juusho wo itadakemasu ka? (May I have your street address?)
- Go-juusho wo o-kaki kudasai. (Please write your street address.)

''please take a seat''

You can say ''Douzo osuwari kudasai''.

how do you ask for someone's home address

You should say ''Anata no jyusyo o oshiete kudasai''.

''Your" is ''anata no'' in Japanese, and ''address'' is ''jyusyo''.

Good luck!