That depends on your version of Acrobat and the way you have it configured. Adobe changes things around quite a bit. I’ll paste below how mine looks.
Click the “Edit PDF” button, like in the above image, and a new top menu will appear, like the screen capture below. One of those menu items says link.
Click the link button and you’ll see several choices.
Click the one that says “Add/Edit Web or Document Link.” A small crosshair symbol will appear. Position that crosshair symbol at the upper-left corner of where you want to draw the link box, then drag it to the bottom right corner and release. A new dialogue box will appear with several choices. Choose the selections you want. For example: “Invisible Rectangle” and “Open a web page” if that’s what you want to do.
Click the “Next” button to enter the destination of where you want the link to go.
Like I said, though, this all depends on your version of Acrobat and how you have your menu items arranged. You might need to search around some to find the equivalent boxes, windows, buttons, etc. in your version. If you’re just using an old version or Acrobat Reader or something similar, you might not have all these options or they might be arranged differently. I’m using Adobe Acrobat Pro DC for Macintosh version 2019.012.20034.