Remember that a freeze is different from a lock.
The credit bureaus are required by federal law to offer a credit freeze. It used to be that they could charge a small fee, but it is now free to freeze and unfreeze your credit. Read more here.
https://www.consumer.ftc.gov/blog/2018/09/free-credit-freezes-are-here
Here is Experian's page for free Credit Freezes.
https://www.experian.com/freeze/center.html
A Credit Lock is something offered by the three credit bureaus because they decided if they have to allow free freezes, maybe they can get some money out of it.
Because a credit freeze is controlled by federal law, the terms and conditions are the same for all three bureaus. You don't have to be a member or have an account, it's free, but it can be complicated to verify your identity. You will get a 10 digit PIN to freeze and unfreeze your account, and if you lose it, you will be in paperwork hell for a long time to prove your identity and unfreeze your credit.
Each company offers their own lock, and the terms and conditions may be different. It might require a subscription or a membership. The company may be able to share your information with marketing partners (if that's part of the terms of service) which they can't do with a freeze. It may be easier to lock and unlock your account than to freeze and unfreeze it, since the company can set their own procedures for recovering lost passwords and so on.
I think I probably have the free freeze at Experian and free locks at the other two.
