I am preparing a template for a client from scratch, drawing with shapes in Illustrator. Client wants the finished product in PDF. I noticed that when I saved it in PDF, my vector shapes are STILL editable if I try hard enough. I do not want the client to have the ability to edit.
So I thought of rasterizing (of course saving my own copy in vector) the shapes and then exporting to PDF, but will this reduce the print quality? Sorry haven't got an actual printer to test.
There are two types of 2d visual artwork, vector and raster.
Vector is a series of mathematical values that define artwork and thus can be scaled up or down by adjusting those values without loosing quality.
Raster is a series of coloured squares (pixels) that make up the artwork. There are only so many squares in any given piece of artwork, so scaling up artwork with a small amount of pixels will make it look blurry and pixellated. Scaling down is generally ok.
With the above in mind, you can rasterise the artwork from Illustrator, just make sure if it is for printing you have the artwork at 300dpi as a standard. You can go less if it's to be printed huge, like a 48 sheet billboard etc.
If they have a printer they are using, you can ask them for the print specification before providing final artwork, that is best practice
Note: If you are printing small text, with lithographic printing where the printer uses separate passes of Cyan Magenta, Yellow and blacK inks. Those passes have to be lined up (registered), sometimes they can be slightly off, which will effect the legibility of the text. So you will need to leave small text as a vector object (type/create outlines) and set it to overprint. This means that the colour of the text will be printed on the colours beneath. DO NOT set very light or white colours to overprint on top of dark colours as it will not print well if at all. (Thanks to @Rafael for pointing this out)