A mob with a name, health and effects. Java with NBT, Bedrock with a name tag.
The /summon command spawns an entity at a point. In Java Edition you can also set the name, health, effects and behaviour directly in the command.
From 1.20.5 some parameters moved into entity components, so the syntax differs from the old one. The tool accounts for the version.
You are not limited to mobs: armour stands, items, boats, arrows and other objects are available through a separate list.
Choose a mob or another entity from the list.
Give coordinates — relative ~ ~ ~ works.
Set a coloured name and a health value.
Tick the behaviour flags you need and add effects.
Check that the spot is not occupied by a block and that you have operator permissions — summons spawn entities, which requires rights.
Enable the NoAI flag: the mob appears but will not move, attack or target anything.