You cannot change your e-mail address yourself: ask for a correction in your account, under Settings › Your data, or write to us from your current address.
Your e-mail address is how you sign in, and where we send your sign-in codes and the confirmation of your purchases. Neither the app nor the website has a way to change it.
To have it corrected, ask in your account on licento.com, under Settings › Your data, and we write to your current address to ask which address you want instead. Or write to us from the address on your account. We act only on a request made from your account or sent from that address, so that your account never goes to someone else. We reply within one month.
If your account has a password, change it with «Change password» in your account's settings: we send a link to your e-mail address.