What type of plant is this
This looks like poison oak. As you probably know, contact with this plant causes an unpleasant skin reaction for most people.
Check out this guide for recommendations on removing it: https://catalog.extension.oregonstate.edu/pnw108
If you're particularly sensitive to poison oak, chemical methods of managing it may be called for so you can avoid contact. According to the publication linked, "..products containing glyphosate and triclopyr are likely to be the most effective and affordable over time." Since it looks like this is in a home garden, check your local retail nursery or garden center for products containing both of these active ingredients. Follow all label precautions and directions. Keep in mind that glyphosate will kill all plants, but triclopyr will only kill broadleaf plants and leave grasses, so if it is in a grassy area, you might want to use a mix containing only triclopyr. Good luck!