This is the type of paper or canvas size that the professionals in Japan use, Manuscript paper type A B4 is 256x363mm with a drawing frame of 180x270mm. Printing size is 220x310mm so they will cut it to the printing size, this is an example on how it will look before it's cut
I actually work with Japanese manuscript paper for when I draw my comic traditionally, and open this in manga studio for when I go digital so that I get the size I want, I then change my canvas to the printing size after I draw. If you want to save this and use it I then go right ahead, I found it online. Sorry for replying twice btw and manga studio does tend to get weird when trying to make your own canvas sometimes which is why I use this, and to be honest I wouldn't go with A4 but that's just me, A4 is usually for Dojinshi but professionals have used it before. I personally like B4 more because it's bigger. Also, before you draw on it or whoever else may download this,
be sure to change the canvas to the printing size so you will know the exact limit of drawing space you have.
