Assuming 5e:

Clerics are a great class, they bring a lot of buffs to the party and given the appropriate Domain they can bring a lot of hurt as well.

Don't pidgeonhole yourself into being a healbot, the majority of the party's healing should come from Short Resting and spending their own hitdice. Playing a healer can be loads of fun if it's what you really want to do, but it can be rather difficult to keep on top of things and it can start to feel like you're not having an effect.

The Life Cleric is the game's "healer" class, and even that gives options for playing more than just a healbot. Having some staple spells like Cure Wounds and Spiritual Weapon always prepared allows you to diversify your prepared spells. Their Channel Divinity option Preserve Life is often the first "heal" you'll actually use, as many combats start very chaotic until more of the enemy are dealt with, spreading healing this way can be extremely effective at patching up the group without spending a Long Rest ability like spellslots and allowing you to use them instead for buffs or damage. Blessed Healer at level 6 gives you more effective healing since you can maintain yourself at the same time using no extra power, combined with your Heavy Armor proficency this puts you very firmly on the front lines.

At 6, a great contribution would be Bless and Spiritual Weapon (which cannot be cast on the same turn, mind). Spiritual Weapon keeps your damage moving while Bless allows 3 creatures minimum (one of which can be you) to add a d4 to all Attack and Saving Throw rolls. A d4 may not seem like much but that's a huge amount of accuracy, and you can add that same d4 to any rolls you make for Concentration on Bless or any other Saving Throw. It can really make a huge difference and should hopefully last the majority of the fight, saving spellslots for other uses.