If you enter it prior to specifying the formatting you are entering it as a date. The number you see when you change to text is the numeric value reflecting the date/data you entered.
Re:Why do we use R rather than Excel?
by formercoder on Sunday July 11, 2021 @11:14AM
(#27801455)
Just type ‘0002.
This is easily falsifiable. In a "general" cell, when I enter 0002, it gets changed into 2, not just in display, but in actual content. When I change the cell type to text, it'll still be 2. Only if I enter 0002 after changing the type to text is the content kept.
Similar when I want to have the text 3/17 or SEPT1 in a cell, I have to format it before typing or the data does get altered. If you try setting it to "text" after you typed it, you'll get some number that's not very useful to you.