If you are beginners, you should always look locally first. Face-to-face lessons will provide your kid much more interest and motivation to improve. S/he also practices against a real person. In the end, s/he will play in tournaments, i.e., play against real people. You can ask other parents, ask your school. Sometime your school offers after-school chess club. Look out for those activity announcement (usually gets home as a sheet of paper), and sign up early. Many times chess classes are hot to in elementary schools.
If you don't have after-school chess club at your school, you can ask your local libraries. Or you search online, typing in chess classes, chess school, chess academy, chess club, or anything similar. Google will give you some clues. Then call them or email them. A mature chess school should have a website.
If you can't find anything, you can talk to PTA and organize an after-school chess club by yourself. You can teach yourself chess as an adult, and teach the kids. The book "Learning chess: Step 1" manual is a good starting point. Every year we give away this book at our "All-Girls Chess Camp", and wish they could learn chess by themselves after the camp.
Or you can ask online, such as in our WeChat groups for chess parents.