If you use the standard documentation, use the <center>
tag like so.
Blueprint
FORMAT: 1A
HOST: http://www.google.com
# Tables
Notes API is a *short texts saving* service similar to its physical paper presence on your table.
<center>
| Tables | Are | Cool |
|----------|:-------------:|------:|
| col 1 is | left-aligned | $1600 |
| col 2 is | centered | $12 |
| col 3 is | right-aligned | $1 |
</center>
# Group Notes
(...)
Preview
If you use the ‘New Documentation’, it’s not possible to center a table (since the table takes a full width of the column).