To allow pop-ups in Safari, the steps vary slightly depending on whether you are using a Mac or an iPhone/iPad.

On Mac

1. Open the Safari app.
2. Go to the website where you want to allow pop-ups.
3. From the menu bar, choose Safari > Settings (or Preferences).
4. Click the Websites tab.
5. In the left sidebar, scroll down and select Pop-up Windows.
6. Find the website in the list under "Currently Open Websites" or "Configured Websites."
7. Next to the website, click the pop-up menu and choose Allow to enable pop-ups for that site.
8. To allow pop-ups for all websites, scroll to the bottom where it says When visiting other websites and select Allow from the drop-down menu.

If you want to block pop-ups again, you can choose Block or Block and Notify instead

On iPhone or iPad

1. Open the Settings app.
2. Scroll down and tap Safari.
3. Find the toggle labeled Block Pop-ups.
4. Turn off this toggle to allow pop-ups globally on your device.
5. When you finish visiting the site that requires pop-ups, it is recommended to turn Block Pop-ups back on to avoid unwanted ads or pop-ups elsewhere

This method allows you to control pop-ups either globally or on a per-site basis (Mac only), balancing usability with protection from unwanted interruptions.