You can a create maximum of 16 indexed columns for a standard table.
In MySQL, you can create an index with up to 16 indexed columns. This means you can include up to 16 columns in a single index definition. However, keep in mind that creating an index with too many columns might not always be optimal for performance and can lead to increased storage requirements. So, it’s essential to consider your specific use case and indexing strategy when deciding how many columns to include in an index.