How can I generate thousands of receiving addresses from a Bitcoin wallet? I want to generate thousands of receiving addresses without sending any BTC to another wallet. Is it possible and how?
Yes, once you have an HD wallet which is free you can generate an unlimited amount of receiving addresses.

There is lots of services offering HD wallet, hardware, mobile or desktop, electrum is a common one, you just have to download and install it, choose and save your secret phrase then you can begin generating your addresses from your seed: https://electrum.org/#download