First, you need to register the email address of 163. Of course, other mailboxes are also possible. Here I take the mailbox of 163 as an example. Register and log in, open the mailbox and click Write Letter:

Click the signature in the letter and the following options will appear:

Click on the previous settings to enter the following page:

Click Add Signature above to set your own signature:

Named "Baidu Experience", the content is "Welcome to Baidu Experience":

Click the Save button below:

Then we'll write another email and see if we can sign it. Click on the signature!

Select Baidu Experience Signature and click:

So the signature is complete.