How to Seal a gap between the baseboard and wall or how to fill a gap or caulk a gap between baseboard and wall can be challenging but you can do it nice and easy using pro caulk tools and Alex caulking.
Tools and materials used:
Alex fast dry caulking = https://amzn.to/3yicqsO
Alex Flex = https://amzn.to/3lWqzHi
Pro Caulk = https://amzn.to/2G6GKQj
Painter's tool = https://amzn.to/32oJpQg