how can i build creadit for my wife and her business, i opened once a capital one card for her, and closed it, i have no idea if she has a credit score or not.

Which Capital One card? Even for a business, most of what matters is personal credit card history. Open another card as soon as you can, because your credit profile looks at a few primary factors: Length of credit: the longer banks have been extending credit to you, the better. Always encourage to open and keep open especially the earliest cards you ever got. Credit utilization: how much of this credit are you using? If they give you $10,000 of credit and your statement closes with 4000 every month, that’s a decently high rate, lower is better. Most importantly I believe: Positive credit use: not having any late fees or interest charged.

there are a lot of free credit scores checkers available for ex ampple https://www.chase.com/personal/credit-cards/free-credit-score?jp_cmp=cc/Credit+Chec[…]teEbvnNqFDtdNU3ydpPYUjQEQyDV-2ydTVwhoCHpEQAvD_BwE&gclsrc=aw.ds

Also, certain business credit cards will not affect personal credit the same way, I would recommend trying both, but especially focusing on getting a few personal credit cards and hold onto them. If you have a lot of credit cards, you want to avoid getting too many personal ones, But if you don’t have, I would recommend getting personal cards specifically as that will show that you are trustworthy to the credit card companies

if she is authorized user on your accounts that should help her too