Web, domains and email
SHA
Abbreviation for Secure Hash Algorithm
In short and in plain language
SHA is a family of methods.
They work out a short check value from data.
Such values are used to sign emails, for example. They are also used in certificates.
Older types are seen as unsafe. So your email and web provider should use newer types.
Definition
SHA refers to a family of methods that calculate a short check value from any data. Such check values are used, for example, in certificates and in signing emails. Older variants are considered insecure, so service providers should use current variants for email and websites.