How does photosynthesis store energy?

As stated in the previous response, the chloroplast is what stores food for later use. Photosynthesis is necessary for the conversion of light energy through the light reaction, also known as Hill's reaction, followed by the dark reaction. Photosynthesis provides the agents required for the formation of energy unit, i.e., glucose or other sugars.

Phloem is also used to carry this food that has been stored to the plant.

I'm open to correction from anyone, cheers!

When photosynthesis occurs, light energy is used to split water molecules into oxygen and hydrogen ions; this process results in the production of glucose molecules, which photosynthesis stores as glucose molecules. The energy from this process is then captured in the form of ATP and NADPH molecules, which are then used in the light-independent reactions of photosynthesis, also called the Calvin cycle, to convert carbon dioxide into glucose.