{tables} is about the tabular environment and related packages such as {array}, {booktabs}, {tabularx}, {tabu}, {tabularray} and {longtable}. For questions about the table environment (i.e., about floating or positioning), use {floats} instead.
tables is about the tabular environment and related packages such as array, booktabs, tabularx, tabu, longtable and ctable. For questions about the table environment (i.e., about floating or positioning), use floats instead.
There are many packages that extend the basic functionality of the tabular environment. A good overview of packages (and package conflicts) can be found in Which tabular packages do which tasks and which packages conflict?. If your question involves one of these specific packages (or another tabular package not listed), you should add a tag for that package as well as the tables tag.
Specific to the positioning of tables as floats, consider reading any of the following posts:
