I can't find the credit sales in any of the financial statements I have. Please help me.

If those are real statements, you won't find it. Real companies don't include that kind of detailed info in their statements, especially considering the published statements of public companies are of a summary nature and not detailed at all.

The statements of fake companies in a textbook aren't going to include it either. It's just going to say "sales," period. The only way you'd get specifically credit sales is if the problem just outright gives you that number. And you'd have to look over the problem to see if they did that.

In other words, you have to learn not to take some of that stuff so literally. People always want to find the exact wording they see in equations. If "credit sales" isn't given, just use total sales.

I have the same problem, so, you recommend me to use the total sales, even if it is too long number, thanks

In your textbook you will be given information needed to solve for credit sales in the problem. The financial statements to use would be the Income Statement, Statement of Cash Flows, and/or the Balance Sheet for the current period and the Balance sheet for the previous period.