By looking on official websites, such as the WHO, we can verify if a claim is true before we pass it on to someone else.
If the information is said to come from a named source, try searching to check if they’ve actually said it. (For example, if it’s claimed that a news organisation reported a fact, try searching for the name of the organisation and a few keywords from the claim.)
If you don’t recognise the source of the information, try and find out. If it’s from a named organisation look them up, examine the ‘about’ page on their website, or search for information about them on Google.
A trusted source is your best option. Check if it is a hoax or fake or scam news. Check Full Fact for fact checks.