What is the correct way to account for spaces in a regular expression?

Question

This is my regex \[BBCODE=[^]]*?\](.*?)\[\/BBCODE\] replacement text is \1 but this works only if text write in 1 line [BBCODE]some text[/BBCODE] but i need to account and whitespaces too, for example [BBCODE]some text here whitespace here and here whitespace loremi psum[/BBCODE]

How i can do that? I will be very grateful and thank you for your attention