replenish vs replace vs renew

 Replenish (Refill or Restock)

Meaning: To fill something back up after it has been used or emptied.
Focus: Quantity and supply levels.
Example: You replenish your water bottle when it is empty, or a store replenishes its inventory on the shelves. [1, 2, 3, 4]

Replace (Substitute or Swap)

Meaning: To take out an old, broken, or unwanted item and put a completely different one in its place.
Focus: Substitution and exchange.
Example: You replace a burnt-out lightbulb with a working one, or you replace an old phone with a newer model. [1]

Renew (Extend, Refresh, or Restore)

Meaning: To start something again, extend its time limit, or bring it back to a vigorous, fresh condition.
Focus: Time extension, contracts, or vigor.
Example: You renew a library book, renew a subscription, or renew your energy by taking a long rest. [1, 2, 3, 4]

If you'd like, you can share a specific sentence you are writing, and I can tell you which of these three words fits best.