Populating Field from one database and posting the result to another

Hello, I am fairly amateur at coding. I am building a job site which accepts applications

Currently I have 2 Databases:

  1. Opportunities (Jobs)
  2. Applications (Job Applications)

I have a dynamic page for each opportunity and the apply button on the page goes to another dynamic page in the same collection for the application form.

To uniquely Identify which application went for which job i have added reference fields between both databases. I have added a input field connected to the opportunity database that is connected to the name and another for country.

How can I make sure that when the user applies. This data goes to the applications database field : “opportunityName” and “opportunityCountry”

I have attached screenshots to better explain. The goal is to identify which opportunity(job) the job application was made. Looking forward to your response. Thank you