No, the grass and any weeds will just die off underneath. But if you plan to plant through the sheeting you will need to remove the turf around the slit that you make or the grass will regrow.

No it will die off. Make sure its fully covered or grass will grow out at sides. Snake

i agree with both members but it also depends on if your grass is raised, i would remove grass and then you have some depth for gravel if it meets a path for example, dont want gravel being kicked about

thanks fellow members for your answers to my query. Much appreciated.
Happy gardening