IPv6 address notation contains eight groups of hex digits separated by colons, digits are case insensitive in use but it is recommended to use lower case in the representation:
You can simplify this notation by omitting leading zeros and collapsing one consecutive run of zero groups to "::" - but this must only be done once, if there is more than one option then the largest run should be collapsed or the leftmost run if equal. Applying these rules and lower-casing letter digits characterize the canonical representation of the IPv6 address.
Leading zeros removed: 2001:db8:85a3:0:0:8a2e:370:7334
Zero group collapsed: 2001:db8:85a3::8a2e:370:7334
IPv6 addresses do not contain square brackets unless when displayed with a port: 2001:0db8:85a3:0000:0000:8a2e:0370:7334.
Data entry: if entered alone, the IPv6 preserve the usual : and :: notation. If it is a part of a URI where a : is expected (like NFS url) then square brackets are mandatory: https://[2001:db8:85a3:8d3:1319:8a2e:370:7348]:443.
Display purpose: if it is a URL and might have a port portion, use square brackets: https://[2001:db8:85a3:8d3:1319:8a2e:370:7348].