Step 1: Search for a plugin called “custom woocommerce checkout fields editor”
Step 2: Install and activate it
Step 3: Go to Woocommerce → Checkout & Register Form
Step 4: Go to the billing fields (or the shipping fields) section and press the add new filed button
Step 5: Fill the fields
Please note that the Name field can contain numbers, alphabets, and dashes but you can’t add spaces.
Type the title of your field in the label vacuum. Ex: Phone Number.
The placeholder text will appear at the background of the field and disappears when you start writing.