You can now add custom columns in your invoice. Follow the below steps to create your own custom columns:
Go to the Line Items table and click on “Add/Rename Columns” on the right corner.
A new model window will appear like this.
Click on Hide to hide the column.
Edit your column name from fields below Column Name.
Add column by clicking on Add New Column.
Give your column a Name and Select Data Type (Data Type can be Text, Date, Number, or Currency).