The most important rule is that products should be marked with the patent number once the patent issues, e.g., Pat. No. #,###,###. Marking products covered by the patent gives constructive notice of your patent rights and constructive or actual notice is required to be eligible for monetary damages.
While your patent application is pending, you have the option of marking your products as Patent Pending. There is no requirement to communicate that there is a patent application pending that would cover the product, but most people want competitors to know that.
Because you have a pending patent application on file, you do not need to worry that selling your product will interfere with your eligibility to patent your invention. Waiting too long to file a patent application after selling or publicly disclosing an invention is when eligibility becomes an issue.