To know if there is a Julia analogue of some Modern Fortran declarations within subroutines

No, there isn’t. Functions · The Julia Language
Some arguments may be mutable (arrays), but others are immutable. Example:

julia> f(x) = (x = 4)                                                                                                                                                                   
f (generic function with 1 method)                                                                                                                                                      
                                                                                                                                                                                        
julia> x = 5                                                                                                                                                                            
5                                                                                                                                                                                       
                                                                                                                                                                                        
julia> f(x)                                                                                                                                                                             
4                                                                                                                                                                                       
                                                                                                                                                                                        
julia> x                                                                                                                                                                                
5