Two things drive this process, one of which is
transpiration. This is how water goes through a plant, from the roots up. Leaves all have these little pores in them, and these powers allow plants to exploit water potential to move water through them. The central principle is that water potential wants to be at equilibrium between two systems, where the plant is one system and the ambient air around it (aka the rest of the world) is another. Water potential generally wants to be equal between them. It’s like when you have a balloon, and then puncture it. Air comes out because pressure within the balloon is higher than the air around it.
Anyway, when the water potential in the air is lower than that of the plant, water moves from the plant outside–exiting through the pores on the leaves (they’re called
stoma, by the way). This, very simplistically, pulls the water in the plant up through it from the roots.
There’s also
guttation, which is closer to plant juice. Guttation is when sap from the plant forms at the edges of a plant’s leaves. It also happens at night when transpiration doesn’t normally occur. When there’s a lot of moisture in the soil, the roots will continue to absorb water, and water just accumulates in the plant. Eventually, this forces some water out and you get little droplets.
Basics of Plant Respiration
https://www.pthorticulture.com/en/training-center/basics-of-plant-respiration/