Lisa

Lisa is the 3rd character that you obtain for free by progressing through the story. Her basic attack procs Electro damage, making it very easy to trigger elemental combos. She can also deal high burst damage using her skill if you apply 3 shock stacks by tapping the skill before you use the hold version, which will deal massive Electro damage in a wide area. Her Elemental burst is also an excellent skill to perform elemental combos since it persists even when you switch out characters.

If you want to to focus her as a damage dealer, you can use 2 piece thundering fury artifact set for electro damage increase, 4 piece is good if you have the team to help with elemental reaction.

If you have limited resources to build/farm artifacts, you can consider two 2-piece artifacts combinations like brave heart, gladiator, martial artist, resolution of sojourner, etc. They can be a safe option since you can then transfer them to a different character if you want to upgrade to a different set.

For weapons, any of the 5 star rarity catalysts are good for damage. As for the crafted weapons, go with Mappa Mare for the damage. The widsith, solar pearl, and eye of perception are also solid options if you get them from the gacha.

Try to bring another damage dealer that can handle some enemies that Lisa can have trouble with, mainly electro type enemies. Since Lisa doesn't have any elementless attacks, you're going to want to bring at least 1 Pyro/Cryo element in your party. Xiangling, or Kaeya are decent options for most players, otherwise most of the gacha characters of those elements are good too.

Qiqi is a character worth putting on the team since she's Cryo and a healer, able to reduce enemies defense from the elemental reaction and works as a healer. There's also Mona for some water elemental reaction to deal high single target damage. Against most non electro resistant enemies, Mona and Lisa can is enough to destroy them easily.

You'll want to focus more on her elemental mastery if you want her to be the support type. Since electro elemental reaction damage are mostly based on your level, you simply need to level her up, then use artifact sets to increase the elemental mastery. 4 piece Instructor is pretty good since it also boosts the team, or just two 2-piece +80 elemental mastery artifact sets (2 Instructor and 2 Wanderer's Troupe).

Alternatively, you can go with a more elemental burst focused type and go with energy recharge artifacts like 2-piece scholar + the exile. There's also Noblesse Oblige for a quick buff to your team by switching to Lisa just for the elemental burst.

Prototype Malice is a really good option if you want to build her support style. This can heal you little by little when you use her elemental burst. This can happen somewhat often if you use energy recharge artifact sets.

"Normal Attack
Perform up to 4 lightning attacks that deal Electro DMG.

Charged Attack
Consumes a certain amount of Stamina to deal AoE Electro DMG after a short casting time.

Plunging Attack
Gathering the might of Electro, Lisa plunges towards the ground from mid-air, damaging all enemies in her path. Deals AoE Electro DMG upon impact with the ground."

"Channels the power of lightning to sweep bothersome matters away.

Press
Releases a homing Lightning Orb. On hit, it deals Electro DMG, and applies a stack of Conductive status (Max 3 stacks) to enemies in a small AoE.

Hold
After an extended casting time, calls down lightning from the heavens, dealing massive Electro DMG to all nearby enemies.
Deals great amounts of extra damage to enemies based on the number of Conductive stacks applied to them, and clears their Conductive status."

Summons a Lightning Rose that unleashes powerful lightning bolts, launching surrounding enemies and dealing Electro DMG. The Lightning Rose will continuously emit lightning to knock back enemies and deal Electro DMG for so long as it persists.