Case 1: Can't remember your password and wish to reset it
You can do this by first clicking on "Sign in" on Ahrefs Homepage.
Then click on "Forgot your password".
By submitting your account's email address, you'll receive some instructions to reset your password in your inbox. Simply follow the instructions to retrieve a new password to your inbox. And you're good to go! :)
Case 2: You know your password but wish to change it
You can do this within your Ahrefs account by following URL https://ahrefs.com/account/my-account and clicking "Change password":
Key in the old password and the new password, and you're good to go! :)