Deactivating automatic changes
Calc automatically applies many changes during data input, unless you deactivate those changes. You can also immediately undo any automatic changes with Ctrl+Z.
Automatic correction of typing errors, replacement of straight quotation marks by curly (custom) quotes, and starting cell content with an uppercase (capital letter) are controlled by Tools > AutoCorrect. Go to the Custom Quotes, Options, or Replace tabs to deactivate any of these features that you do not want. On the Replace tab, you can also delete unwanted word pairs and add new ones as required.
When you are typing in a cell, Calc automatically suggests matching input found in the same column. To turn the AutoInput on and off, set or remove the check mark in front of Tools > Cell Contents > AutoInput.
Automatic date conversion
Calc automatically converts certain entries to dates. To ensure that an entry that looks like a date is interpreted as text, type an apostrophe at the beginning of the entry. The apostrophe is not displayed in the cell.