economy

The Fed is really the only government agency that would be able to make the dollar appreciate vis-a-vis foreign currencies.
It would do this by raising interest rates, making it more attractive for investors to hold their investments in dollars, as higher interest rates pay larger returns to foreign or domestic lenders. Ie, the countries with the highest interest rates will have the most highly valued currencies.
Higher interest rates are sometimes necessary to reduce inflation; however they also contract the economy and can cause recession. The Fed could certainly stregthen the dollar if they wanted to; to do so may risk a recession.
A less highly valued dollar will also benefit our exports; lower interest rates help businesses, consumers, and the stock market but may, over time, cause inflation.
(The other postings discuss stuff that isn’t really relevant to any sort of economic discussion.)