Since release update wordpress version 4.7 features underline and justify removed by wordpress. So many people who find it difficult or confused if you want to set the text wants to underline or want to make writing to be left right flat.
There is actually a simple way to overcome this, you can use the shortcut. Eg for underline / underlined text you can use Ctrl + U key, for left right writing, you can use Shift + Alt + J. Or you can click the (?) Button to see other shortcut feature. The problem here, not everyone knows the function of this shortcut button, because the habit of staying click the existing button.
To overcome this, you do not have to worry, you can use additional plugins to bring up the missing button again.
Following Raises Button Underline Feature and Justify In WordPress 4.7 Up:
Try to try to open the page add post or Add page, then feature button Justify has reappeared.
Thank you for reading this post may be useful.