Might be easier to use curl commnad .. in a notebook you can run as shell command or python to first load the file into local driver temp storage

%sh curl https://url.com/file.pdf --output /tmp/file.pdf

 or in python

import urllib
urllib.request.urlretrieve("https://url.com/file.pdf", "/tmp/file.pdf.csv")

Then move the file to DBFS

dbutils.fs.mv("file:/tmp/file.pdf", "dbfs:/Filestore/file.pdf