Access online Transunion, Experian and Equifax and create a account. You can search each of these names with the words credit freeze and the search results may shorten your efforts. At least one of these services has multiple types of accounts but all 3 have free accounts available.
You can call 1 or more of these and do a credit freeze over the phone but I would recommend setting up the account on each. Once the account is set up then you can request a credit freeze, review personal information, credit card account information and such. If you see anything out of line you that you desire to change or delete they refer to it as a dispute. You need to review your information on each of these sites because the information usually varies between sites.
Since login requires my SS does this mean my wife must sign into her own account and freeze under her name?