The phrase "tech-savvy" describes a person who knows how to use computers, mobile phones, and other electronic devices well.

The word "savvy" means "smart" or "well-informed". However, it isn't as common as something like "smart". It appears in a few other combinations:

It seems like some of the younger members have more business savvy than some of the higher-ups.

She's intelligent, charming, and has a lot of political savvy. I'm sure she'll go far.

Even the savviest investors can't predict what's going to happen in this market.