What are some activities that cells engage in that require energy? And from where do cells obtain the energy they need to make ATP?

Some activities that cell requires energy may include cell division, active transport, protein synthesis etc.

In human, Cells get their energy by the food we eat. The nutrients in the food breaks down into soluble and simple molecules in stomach and small intestine and it is absorbed through the small intestine and assimilated into the cells, becoming part of it, providing the uses for each type of nutrient. And of course, many of them is the energy source.