How do i make an animation play on click?

To make an animation, you need an animation object. If you want to learn more about animation tracks, click here

Use LocalScript

& add script to tool

I'm going to explain everything with detail so that I'm not just throwing in a script.

If you don't already have animation object then do add one or add a variable like this to create one.

local AnimObj = Instance.new("Animation", (Choose parent))
AnimObj.AnimationId = "rbxassetid://Your Animation ID from URL"

To get animation track, you need to have an animation object. You might already have that. If so, then locate your animation and make it a variable. Also player. For example,

local player = game:GetService("Players").LocalPlayer
local AnimObj = workspace.AnimationA -- if you already have animation object

And then you can find Character from LocalPlayer. Also Humanoid is needed. Once again, this is a LocalScript

local player = game:GetService("Players").LocalPlayer
local AnimObj = workspace.AnimationA
local char = player.Character or player.CharacterAdded:Wait()
local humanoid = char:WaitForChild("Humanoid")

Now we need an AnimationTrack, so, let's create a new variable.

local player = game:GetService("Players").LocalPlayer
local AnimObj = workspace.AnimationA
local char = player.Character or player.CharacterAdded:Wait()
local humanoid = char:WaitForChild("Humanoid")
local AnimTrac = humanoid:LoadAnimation(AnimObj)

Time to set Priority to Movement, so it plays over the original holding animtion, if you already did this in Animation editor then good, but if you didn't, there's a property in AnimationTrack which is Priority, so add this to the script:

AnimTrack.Priority = Enum.AnimationPriority.Movement -- do movement or action, i recommend movement if you want something else to play on top of it

Finally, let's use the Tool.Activated event and play animation. That's when the player clicks. If you want to learn more then click here.

AnimTrack.Priority = Enum.AnimationPriority.Movement -- do movement or action, i recommend movement if you want something else to play on top of it
script.Parent.Activated:Connect(function()
    AnimTrack:Play()
end

You can add debounce if you want, but i'll leave it here, you can add what you want, I hope you learned something new, and I hope this worked for you.