Whew, the terminology in this thread is all over the place.
On the W-4 form, you claim allowances. Allowances do not equal the number of people in your household. They don't equal the number of personal exemptions that you take on your taxes (which are actually not a thing any more under the current tax law). Allowances are a somewhat convoluted way of estimating your tax due at the end of the year based on household composition, earnings, and expected deductions. The two-earner/multiple jobs worksheet is VERY important if you're married or have multiple jobs. Your employer only knows what they pay you and the tax tables - allowances are a standardized way of adjusting your withholding based on your specific tax situation.
I'm not sure how much each allowance is "worth" this year, but it looks like it was $4,150 in 2018.
Fill out the personal allowances worksheet on the W-4 form, as the instructions direct you to, and get a good number. The online IRS withholding calculator also used to be helpful (though I just tried it for 2019 and I can't make sense of the results, soo....).