To set a login name on Shopee, you can follow the steps below:

1. Open the Shopee app or website and log in to your account.

2. On the homepage, tap the profile icon in the upper right corner.

3. On the profile page, find and tap the "Settings" option.

4. On the Settings page, find the "Account & Security" option and tap to enter.

5. On the Account & Security page, find the "Login Name" option and tap the Edit button.

6. Enter the new login name you want to set and make sure it meets Shopee's requirements (such as length, character limit, etc.).

7. Click the Save button to confirm and apply the new login name.

Please note that according to Shopee's policy, once you set a login name, you will not be able to change or delete it. Therefore, please make sure you choose a login name that is easy to remember and related to your identity.