Need a receipt for a Roblox account that I don’t know my password too

Loder,

Assuming the original purchase was made through your Apple ID, look in your Purchase History. It will have all your purchases, and you can find the one you want from 2017. Use the steps in here:

View your purchase history for the App Store, iTunes Store, and other Apple media services - Apple Support

Once you find it, click on "Resend" (as below) and it will email you a new copy.

Loder,

Find the item you want, and open it.

If you are looking at your Purchase History on a computer, the Resend link is below the "billed to" information, as shown in the picture.

If you are looking on an iPhone, the Resend link is near the bottom of the screen.