Click your account menu in the top right of the screen, then select Profile.

This opens your employee profile on the Work tab.

On the Work tab, look for the Designation field. Directly below it is Job Level, the level inherited from that designation.

If your designation has a level assigned, you'll see the level's name, often with a rank number next to it, for example "rank 3". If your designation doesn't have a level yet, the field shows Unlevelled. That isn't an error, it means an admin hasn't assigned a level to your designation yet. While your level is loading, you'll briefly see a dash (—) instead.

Hover over (or tab to) the ? icon next to the field for a short explanation of where the level comes from.

You can't edit Job Level yourself. It's always derived from your designation, so there's no separate control for it on your own profile. If you think it's wrong, ask an admin to check your designation's level.