On the Xiaomi smartphone, we can edit the contacts as we like and add numerous details such as birthdays, addresses or URL's. The following detail fields are available:

Note: In this guide we will edit an existing contact and just add a web page.

Android 10 (MIUI 12.0)
Step 1:  Open the  Contacts app
Step 2:  Choose a  contact
Step 3:  Tap on  Edit contact
Step 4:  Tap on  Add another field
Step 5:  Choose a  field/detail
Step 6:  Enter the appropriate  data
Step 7:  Tap on  Save
  1. Open the Contacts app
  2. Choose a contact
  3. Tap on Edit contact
  4. Tap on Add another field
  5. Choose a field/detail
  6. Enter the appropriate data
  7. Tap on Save

Xiaomi Instructions