Question using different app to open a file -?

[melani78]

Im having alot of problem trying to work out on my samsung galaxy phone - how to use a different app to open an extension, in this case I accidently pressed X-plore to open a *.pdf file , it cant open it - I do have pdf reader files on this mobile, on a pc its very is- how do I change -use a different app to open a file on android ??