Excel will automatically make assumptions about the data. Like in Python and other coding languages, there is no datatype. The values of cells can be tested using functions.
Functions to look at istext(), isblank(), isnumber(), islogical(), iserr(), ...
so if you want to know the data type in B5.
=IFS(ISTEXT(B5),"String",ISBLANK(B5),"Null",ISNUMBER(B5),"Number",ISLOGICAL(B5),"Boolean",ISERR(B5),"Error")
Use a single quote before the number, such as "50," to turn it into a string. In Excel, a date is also a number. Multiply by 1 to change a string-stored number into a number.