Assuming you and your tenant have filed ONLY GSTR3B yet, Show in your july GSTR1 as taxable supply and pay tax. collect the tax amount from tenant, which was not earlier paid by him.
@ AMIT., When you registered under GST then you ll be give taxable invoice/Receipt to your tenant.... Before Registration they ll pay Tax under RCM basis if they are registered. They are not registered then no need RCM...
After your registration you ll be give invoices/receipt as above said way..
You received on August. So, you have to raise invoice on receipt date as per time of supply rules, By that you have to file nil return for July month... For the month of August in GSTR 3B you have to mention the value of receipt taken
"The time of supply of services shall be the earlier of the following dates:-
(a) The date of issuing invoice (or the last day by which invoice should have been issued) OR (b) The date of receipt of payment -whichever is earlier"