not sure
when we declare variable in procedure or function

Never heared of Option Implicit.
Though Setting Option Explicit "ON" requires declaration of 
variable before that variable can be used.

Instance of specific copy of a class with its own settings 
for the properties defined in that class. Note: The 
implicity defined variable is never equal to nothing. 

Option Explicit has 2 values ON and OFF
deafult value is ON
-Option Explicit means - All the variables should be 
declared before its use.
Else it shows error..it is a good practice to use this..

Option Explicit is set to On, to declare the variable 
compulsarily.
if u set it to off, the user who is going to read your 
coding won't find it easy to know what type of variable it 
stores. i.e int, float, string, var, etc.,

can i able to change my vb6 form style

Option Explicit means - All the variables should be 
declared before its use.
Else it shows error