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