In how many ways we can set Field level security in Salesforce?

In Salesforce we can manage  field level permissions in three ways.

1. By using “set field level security” button from field detail page .

For example you want to set fiels level security for field Account Number on Account object.       Account'(setup>object manager>Account>Account Number>set field level security).

2. By using “view field accessibility” button from field detail page.

3. In profiles/permission sets we can manage field permissions.