I want the federal government to support people who need help, even if I don't know their names, locations, or situations. It has done less of this recently.
Primarily, I want them to support US citizens & residents & workers, and that is where a substantial amount of federal spending used to go, but morally I feel that people worldwide should have access to the basic necessities of life - food, water, shelter, medicine. That's a common sentiment among all major religions, for example:
... but the people talking most loudly about this being a "Christian nation" have also made it clear they don't want to help the poor, and view any such aid given to the needy as fraud.
I also want the federal government doing research - for solutions that aren't obviously profitable, or into problems that we don't yet understand. I also want the federal government improving education nationwide - hiring people with skills which are _not_ mine, hiring teachers and providing resources I don't have the time or resources to provide myself. I want the federal government researching problems & solutions I don't have the time to critically judge.
Small organizations, funded purely by voluntary donations, are not up to the magnitude of the challenge. High-profile causes backed by the rich and the powerful do not map reliably to the needs of the majority of people. I try to help the poor, and to back scientific research into problems that seem important to me - especially where the federal government is failing to provide sufficient support - but the federal budget is more than six orders of magnitude larger than my own. Economies of scale are an important consideration, even for charitable and educational work.
Corporations should give more - they benefit in the long term from a larger, healthier, better-educated population, but the current system rewards pursuit of short-term profits and shifting burdens to competitors and alternate solutions while selfishly reserving rewards for one's own company.
Wealthy individuals should give more. Their wealth is ultimately backed by the stability of the economy, and by the quality of roads & health care & emergency management for the country & world as a whole. But they also have come to believe that they deserve vast sums of money drawn as tithes from the prices of everything we consume.
Neither corporations nor wealthy individuals have an enforceable obligation to help the poor, or to help the country as a whole. They know it and they take advantage of it. But this government claims "We the people of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America."
Such a government _must_ be responsive to the needs and desires of its citizens as a whole, not merely to the whims of a few wealthy individuals who hide their identities and motives.
Call your representatives regularly, and vote like your life depends on it. The only alternative is to continue to sacrifice your blood, sweat, and tears to make billionaires richer and less accountable.