If your advocate opened an account for you, this is where you sign in. Your password was chosen by you, in your own browser — nobody at the practice can see it, and neither can Legatio.
Accounts are opened by your advocate, never from this page. If you do not have an invitation, ask them for one.
There is no way to reset this password. Nobody at the firm can recover it, and neither can Legatio. If you forget it, your advocate has to invite you again, and that starts a fresh conversation: the messages in this one will not come with it.
Some matters are still reached by a link rather than an account. A link opens on its own address and is not signed into here: find the email from your advocate, open the link on this device, and enter the 6-digit access code they gave you separately.