Goods and sale invoice

You can create a ledger named "Service Charges/Fee " or "Installation Charges" or any other name as suitable and put the same under DIRECT INCOME / OTHER INCOME

If 2 lakhs is installation then where is the gst?

Two classifications are allowed 

Income from Sales

Income from Services

All othwr classifications can be alias.

Direct income/ sales varies based 9n the software

Ok I got the gst part, you have to show it net of gst and  only under sales cquse i changed my mind. Services are sold.