Many services vs keywords?

I recently did an SEO course and I came across something I didn't find whatsoever in the course. And my issue is if you have a website that offers many services, and it would be great help to post many keywords to each specific service. But I am not sure if that would be considered keyword stuffing. Upwords to 50 different services.... How can I tackle this situation because putting simple keywords in there for all the services would have me massively competing against million dollar websites and companies. Or are the keywords allowed?