The list below shows all the "type" of columns you can select from when creating a database...
Below is a list of the maximum character limit for text and number fields...
Text > up to 255c
Long Text > up to 50,000c
Formatted Text > up to 50,000c (note, this is 50000 characters of HTML, not the number of visible characters)
Phone Number > up to 255c (any of the following "0123456789 - + ext ( )”)
Email Address > Valid email up to 255c (ie. must contain @ and at least one ‘.’ in the domain)
Number > Any numeric value between -900000000000000000 and 900000000000000000.
Select one from List > up to 255c for "each" selected value
Select many from List > up to 50,000c for "all" selected values
File > 20GB (maximum per each upload)
Picture > 512MB (maximum per each upload)
Note: you cannot change a column type after creating it using a specific field, eg: "text" but require changing it to "long text" as you need more characters.
You'll have to modify the existing database by "adding a new column" and selecting the new desired "type" field, click save.
Then you'll need to re-order the database columns along with copying any existing data from the old column to the new one.