Book of shadows allows this

choose three cantrips from any class’s spell list (the three needn’t be from the same list)... If they don’t appear on the warlock spell list, they are nonetheless warlock spells for you.

Quote from Herodragon33 >>

Getting spells outside your class is a question for your DM

My comment was in response to someone wanting their wizard to have the spell

Ah I see now, missed that part of the discussion.

If the DM allowed it they could be human variant, set their background as acolyte and take the Magic Initiate (cleric) feat. 

I'm a bit disappointed that noone pointed out that this can be used to give a Counterspell or Dispell Magic check a 1d4 boost, since they're an ability checks, which makes this cantrip so much more useful.

I'm not seeing anything about whether the effects of guidance can stack or not. Obviously the caster can only cast it once on a person because it is concentration, but what if you have multiple casters? For example: if the party has 5 clerics for some reason can they all cast guidance on one person at the same time and have that person roll an extra 5D4 to add to their check?
I'm imagining a group being at a church of Gond or something where there are tons of clerics and the room of clerics is just consistently giving the party a buff of like 20D4 on all their checks as they forge some divine weapon to face the BBEG with.

Quote from AnderzDraconian >>

I'm not seeing anything about whether the effects of guidance can stack or not.  

According to Sage Advice, game features (class features, spells, etc) with the same name don't stack with each other.

Can this spell be used on party members ability to help make a spell stick?? 

Quote from jsper07 >>

So can you use guidance when the DM says, "you can roll for a perception check" for example, or it needs to be done before that ever happens?

 No, you need to do it before hand.

For those who have guidance, it's fairly normal to ask the DM if you can keep it up all the time by recasting it every minute and after its used. In which case, yes you'd have it available for perception/initiative/traps.

I can't ad this cantrip to my character sheet.

Did you ever get an answer on this?

So helpful. My exact thought.

Can one player use the help action and another use guidance for the same roll?

Yes, you can add Help and Guidance together, they are completely different effects. Same with Bless and the Peace Cleric's pseudobless domain feature, since they are all different spells/spell-like abilities! Of course, you can't concentrate on Bless and Guidance at the same time, but you might have a couple of different divine casters in your group (eg Peace Cleric and Druid) if it's big enough.

Many players don't realize that initiative is an ability check. Per the PHB, p. 189: "When combat starts, every participant makes a Dexterity check to determine their place in the initiative order."

You can add 1d4 to your initiative if you cast Guidance prior to the start of combat. However, the spell needs to be cast such that doing so doesn't itself serve as the trigger for initiative (as would, say, casting Fireball or taking any other hostile action).

I want to use this spell but I also don’t want to be terribly annoying by using it too much and too often. A strange problem but I just don’t want to irritate my dm or the other players with it because I can definitely see how using it constantly would be so. Like I said it’s a bit odd but any tips? I could just be worrying to much about it though. I have a tendency to do that. 

I doubt the other players would be too bothered by the 1d4 buff. I'd suggest coming up with a short phrase your PC uses to convey the blessing. Something like "By the grace of [deity]" would be appropriate.

Can this stack? 

For example: Person 1 cast guidance on Person 2 and the Person 3 also casts guidance on Person 2. 

So then would Person 2 then be able to roll 2d4 instead of just one and can they save one of the d4s for later?

Quote from ClericalKenku >>

Remember that this has no effect on saves or attacks.

 a save is an ability check, but an attack is not

/bump

Quote from MatStumpy >>

Quote from ClericalKenku >>

Remember that this has no effect on saves or attacks.

 a save is an ability check, but an attack is not

Quote from MatStumpy >>

Quote from ClericalKenku >>

Remember that this has no effect on saves or attacks.

 a save is an ability check, but an attack is not

No. A "Save" is a Saving Throw and a "Check" is an Ability Check... and Guidance only applies to Ability Checks.

You can add this to any skill checks (including Initiative), but not Saves.

I'm sure it is a cost/effect situation. It is a cantrip after all, not a spell that requires resources (spell slots).