So this is my first time playing in a DND campaign and my paladin character learned spells like the Light Cantrip, Moonbeam, and See invisibility

So I know all these need components but how would i go about getting the stuff for them?  I dont have a components pouch so would i need to travel to specific places to get the materials i need before casting them??

Paladins can use their holy symbol as a spellcasting focus. So you only need components for items that specify having a material cost or if the spell specifically states it consumes the material components (eg Revivify). But if you did want to have spare fireflies for casting Light, you could talk to your DM about gathering those either from nature or from shops, depending on the component.

I look on my character sheet under "Equipment" and - bam! - there's my component pouch.

But to be serious, it can vary widely between different DMs and how they want to run it.

Some say your component pouch always has the stuff you need, and if you require a component with a cost, you just pay the cost when you cast the spell and say you had already bought it.

Some say your component pouch has all the no-cost consumables you need, but if a spell consumes something with a specific value, you need to have that thing.

Some say you need to restock every time you go into town and you may or may not need to pay X gold to do so.

Some say you can forage for all the no-cost components you need during rests.

Actually having specific things you need to do to collect specific components for specific spells - while that seems cool and compelling, it has the likelihood of quickly spiraling out of control as you get higher level and have so many spells to keep track of and thus components to get. When you have 3 hours to play, the other players might object to half of that time spent on describing how the druid gets the components she needs. And then when she realizes she needs a prepare a different spell the next day, off she goes again...

It might be a cool thing to do by email or as a solo thing between games though. Or maybe a bit more interesting if the whole party needed components.

I also enjoy when components are worked into treasure the party is getting anyway. For example, in one game he pearl I use for identify used to be the an earring worn by a pirate wizard we defeated. It's just way cooler than if it were just a pearl I bought at a jewelry shop or something.