i'm new to solidworks, right now i'm working on an assembly, and i'm trying to add a feature, is it possible to extrude a blind sketch while in an assembly file.
Thanks
Nope! You can only cut extrude in an assembly. If you need to make an extrusion you have to make a part and insert it into an assembly. YOu can manipulate the part once it is inside the assembly.
Like SBaugh said, you can manipulate parts within the assembly. Right-click on the part's icon in the assembly manager tree and select "Edit Part". When you are done changing the part in-context, right-click on the icon for the top-level assembly and click "Edit Assembly".