Because so much scholarship is available online, most reference list entries will end with either a DOI or a URL; these enable readers to easily find the source of information in the manuscript. The DOI should be included for all works that have a DOI. If the work has both a DOI and a URL, use the DOI. DOIs can be found by going to https://search.crossref.org/references and entering the reference entry. DOIs begin with https://doi.org/ followed by numbers and letters that identify the document. The identifier begins with the number 10 followed by a four-digit number assigned to the publisher. This is followed by a forward slash and combination of letters or numbers that the publisher creates for each work, e.g., https://doi.org/10.1002/cae.22076 and https://doi.org/10.28945/4526 

URLs begin with either http:// or https://

The best way to make sure that the URL or DOI is entered correctly is to copy it from your browser and paste it into the reference. Do not add line breaks manually into the hyperlink; let the word processor insert any necessary line breaks. Do not place a period at the end of a DOI or URL. For more information, see https://apastyle.apa.org/style-grammar-guidelines/references/dois-urls