A common misconception I encounter all the time is "won't freezing my credit prevent me from improving my credit rating?" Absolutely not. Freezing your credit simply prevents any organization from pulling your credit report without your direct approval, that's all. It has no other effect on anything. Maybe "freezing" is a bad name for the practice and leads to confusion , but that's what it's called.
Freezing and unfreezing your credit reports is quick and easy to do once you've created accounts at the big three agencies, Experian, Equifax, and Transunion. First create accounts on these three sites:
Experian: https://www.experian.com/help/login.html
Equifax: https://www.equifax.com
Transunion: https://service.transunion.com/dss/orderStep1_form.page
They will try to sell you all kinds of premium deals and other crap, skip all that because you don't need any of it to freeze/unfreeze your accounts even if the wording makes it sound like you do. Once you have accounts and are logged in, these are the links directly to the free freeze/unfreeze pages:
Experian: https://usa.experian.com/mfe/regulatory/security-freeze
Equifax: https://lockandalert.equifax.com/member-center/portal/
Transunion: https://service.transunion.com/dss/freezeStatus.page
Some give you the option to schedule a freeze, but I usually just manually do it myself. So any time you need to have your credit checked (like when getting a new credit card or a bank loan), log in and unlock all three, and once the inquiry is done, go back in and freeze them all. It takes less than five minutes to do all three so there's no reason not to do this. If you can find out from the creditor which agency they use, you can just unfreeze/refreeze that one.
There are a TON of apps and sites out there that will offer to manage this stuff for you. But they all exist, of course, to try to sell you things, or at best, sell some of your info. Since it's so easy to do yourself, I recommend skipping all those third-party apps.