See general advice for preparing tables here. If using Microsoft Word, you should make tables using Word's table function. Don't embed excel tables or PDF tables, as these can't be read by all journal submission softwares. Avoid using merged cells, putting returns inside cells or using special formatting as these can get corrupted. Check with your journal to see if they want your tables to be embedded into the manuscript or kept separate.
Every table should have a title. Generally it's best to keep this title short and put any detailed explanations into footnotes, but check to see what your journal wants,