I would like to make a Fighter who through multi-classing could cast True Resurrection and has access to the Barbarian's Rage and Unarmored Defense. Could this be done? How would I put this on a character sheet?
When multi-classing, you cannot pick specific features of different classes and combine them — you pick levels in those classes (rules about multi-classing, also check the Player's Handbook page 163 for more details). For example, a level 4 character can have 2 levels in the fighter class and 2 levels in the wizard class — they will gain all the features of a level 2 wizard and all the features of a level 2 fighter. It is a bit more complicated when multiple caster classes are involved and there are some requirements when it comes to ability scores.
In other words, to get all the features you want, you need to figure out which classes have access to them, at what level, and take enough levels in that class to reach those levels. The barbarian's unarmored defense and rage is a level 1 feature so that's easy. One the other hand, true resurrection is a level 9 spell that's available at level 17 to clerics and druids. That leaves room for 2 levels of fighter, assuming that your character is level 20.
Note however that at this point the character would be more of a cleric/druid, with a few levels in barbarian/fighter. Also, while using the barbarian's rage, you won't be able to cast any spells, so the synergy isn't very good.
A possible low level alternative would be picking one level cleric or druid that will allow you to attempt to cast True Resurrection via a scroll. It would be a DC 19 check, based on your spellcasting ability (Wisdom) and if it fails the scroll is destroyed. It might be possible to avoid the check you could take 13 levels of thief rogue that allows you to use a magic device, although it's a bit unclear whether that's the case. Keep in mind that a level 9 scroll would be extremely rare and possibly quite expensive though.