Are certifications worth it while job hunting? - what worked for you?

I saw that many postings ask for a specific certification. I worked as an administrative assistant before this. I am unsure whether employers value it. Which ones are overrated?

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.

A hands-on course with a project helped more than a purely online one.