How to evolve Pansage in Cobblemon

The full line is Pansage → Simisage. Here is exactly what each stage needs.

Leaf Stone

Stage by stage

Evolves into	Requirement	Type	BST
Pansage	Base form	grass	316
Simisage	use Leaf Stone	grass	498

If it evolves by level, nothing else is needed. Just battle and it happens.
If it needs a stone, those are mined as ore or crafted. Some have biome bias, so a stone you cannot find is usually in a biome you have not visited.
If it needs friendship, walking with it and levelling it up both build that. A Soothe Bell speeds it up and Luxury or Friend Balls start it higher.
If it needs a trade, a Link Cable simulates one so you do not need a partner.
An Everstone blocks evolution if you want to keep the current form.

Full stats for each stage are in the Pokedex, and breeding covers passing natures and IVs down the line.