UPDATE: For reasons beyond my understanding my first reply vanished while I thought I was still editing and previewing it prior to creating it. The page was replaced by an prepopulated Super Search that had no obvious connection with any word or concept in the reply. So I created this (from scratch) to make pretty much the same point... and found my prior effort already in the thread.

So I'm baffled. Reap this if that seems advisable... or leave it be, if it has some clarity-value not present in the previous.

UPDATE 2: Since OP has responded that my previous post answered the question, maybe this should be reaped.

Why do you ask? And, what are you asking about:

1. Sharing a uname/pw with someone who might use them to log in at the same time you're onsite?
2. Creating multiple unames/pws for yourself?
3. Logging in from multiple devices, simultaneously?

The answer that comes immediately to (my) mind, based on the unclear question, is a resounding and utterly unambiguous "maybe."

maybe because (1) is idiotic; (2) is deprecated here, if used for voting; and (3) why on earth would you do that?

Perhaps you can make your question intelligible by answering some of the questions above.