Who knows maybe that actually ran a process on background and downloaded a malware. You can't be sure of things unless you start to see changes or something unusual with your device. Sometimes you can't notice them at all. Maybe its a scam where you have to call the number but what if they take it up a notch and make the pdf contain a malware also, in case if the phone call attempt fails.
Maybe running an antimalware is a measure but I don't think its gonna fully work. Best thing is to reset the device where you have run it after making a backup. Another thing, turn off the remote desktop on your device.