I need to build the form dynamically based on the data source data.
Here I am using excel as a data source.
In this excel I have used the 3 headers.
If I changed the field name or add the one more header, the canvas app automatically build the screen based on the data source date while I navigate to that screen
Canvas app is actually meant for WYSIWYG app maker (low code), so there is no OOB way to achieve this dynamic control creation on load of a dynamic form layout. Read more
But anything is possible, using code logic to generate a field or show/hide and it may be messy to do in same form load. Probably you can develop a component or even PCF control to generate the control based on excel config data (control, data type and properties). You can get some idea from this video tutorial.