can top stitching be done by hand? i don't have the machine for that?

Yes. Remember that all sewing was at one time done by hand.

you can use your regular sewing machine, no special machine is needed.
You use the straight stitch for basting, seaming, and topstitching.

It may be difficult going through all of the layers, but yes, you sure can :D:D:D

If u use your machine you can get a top stitching needle. They somewhat cut as they go thru the layers rather than trying to stab thru the heavy layers. Makes it much easier.

what is it you are top-stitching?

is it a design feature?- is it tote bags/purses?
is it decorative pillows?
knowing what it is you want to top stitch will help us give you any tips on successfully doing it-
but pretty much any and all sewing can be done by hand-with the right tools.

Your project your choice, no sewing/quilting police here.

If you can top stitch by hand through all the fabric thicknesses, then you can surely do it by machine with a simple straight stitch.

Yes you can