I just did this and for Equifax and TransUnion, it was very easy, you just download the app and fill in some information. Experian looks like I will have to mail in a request with some documents.
> Unsurprisingly, the bureaus’ use of the term credit lock has confused many consumers; this was almost certainly by design. But here’s one basic fact consumers should keep in mind about these lock services: Unlike freezes, locks are not governed by any law, meaning that the credit bureaus can change the terms of these arrangements when and if it suits them to do so.
https://krebsonsecurity.com/2018/09/credit-freezes-are-free-...