According to APA 7th edition style, a DOI URL should start with:
https://doi.org/
and continue with the DOI itself, which always begins with the number 10 (for example: 10.12930/NACADA-18-30)
So, here's what a DOI URL will look like at the end of an APA reference citation:
Karmelita, C. (2020). Advising adult learners during the transition to college. NACADA Journal, 40(1), 64–79. https://doi.org/10.12930/NACADA-18-30
For more on APA 7th citation check out this from Purdue Owl and APA Citation Style Guide or check out this YouTube Video