I have seen this phrase in many articles. It sounds a little bit odd to me.
Also, what could be an alternative to this? Can I use "please be aware" or "For your information" instead of this phrase?
Yes, "Please be informed that..." is correct, as is "For your information".
Both formulations are common and current.
The former is considered more polite, and is the accepted form in written communication, but it can also be used sarcastically in oral communication by a speaker who wishes to assert authority over a subordinate.
The latter is used in spoken conversation except when particular formality is required. It can also be used assertively but is not an inherently assertive formulation.
'Please be informed that' is more polite than 'This is to inform you that'. The latter implies authority, so the 'you' becomes an object.
In other words, an object is supposed to be passive, if not powerless.