The second box is an example URL to a PDF file, you can enter the URL to whatever PDF file you want.

The first box is just a description, you can enter whatever you want, for example Open PDF in browser.

That will open a popup with five text boxes and two checkboxes. Next, click on the three dots on the top right, scroll down, click 'Redirector', then click on the 'Edit Redirects' button, and then click on 'Create new redirect': Once you've installed Kiwi (or another browser that supports Chrome extensions), install the Redirector extension (I have no association with its author). The one I use is Kiwi (I have no association with its author). Unfortunately, you can't do this on any well-known browsers (Chrome and Edge for Android don't support extensions at all, and Firefox for Android only supports a very limited set of extensions), but there are less well-known browsers where you can do this.

However, if you use a browser that supports extensions, it's possible to use an extension to automatically redirect PDF files to this URL. Unfortunately, there is as far as I know no way to do this automatically in Chrome (you can always paste the URL manually every time you want to open a PDF file but that's not very practical). To do this, visit the page, where is the path to the PDF file you want to view (credits to this answer). You can use a Google Docs page to view PDF files in the browser.

Adobe pdf android browser