Read customer reviews
The first thing to do is to search the Internet for resume services or writer reviews. Make sure these reviews are taken from a third-party site where clients can leave reviews.
There are many fraudulent sites that publish fake reviews, so use common sense when reading reviews.
Another way to get real feedback is to go to your network and see if anyone has used a professional resume writer or professional resume writing service. Note that it's easier to find feedback on a service than from a freelance writer.
Check the location
You should make sure that the writer or service you are using is in your country or has experience writing resumes for the country where you are applying for a job. There are differences in how resumes are written for different countries.
The best way to avoid working with an outside copywriter is to contact customer service or ask to speak to a copywriter by phone. This should be a red flag if your department doesn't have a customer service number or you can't reach the writer by phone.
Find the process
Make sure you know what the process will look like before you choose a resume writing service. Many services will ask you to fill out a form and send you a resume. The only way to get a quality resume is to work with its copywriter.
This means that you should be able to call the writer or exchange emails to work on different reviews. You should also make sure that you can request corrections to your resume after the project is submitted. A service that does not offer or limit reviews should be red flagged.
Nearly 75% of resumes are rejected by ATS systems, and several times a candidate qualifies but their resume is not optimized.
Find writers
You should see profiles of some of the copywriters working for the service you are considering. A service that doesn't have its writers listed is another red flag to outsource.
Some certificates are also offered to services and writers.
Check the price
Price is another important factor when choosing a resume writing service. Resume writing services, mean that the writer won't spend a lot of time on resume editing or outsource it to a substandard copywriter.