To my understanding, you are trying to write a string in a textbox in line 1. Then followed by another string “Flag:” and a number as a string in line 2. You want to bold the term “Flag:”. Please have a look at the code below to perform this operation
str = 'String in line 1'; %string for line 1
x=2; %number to be treated as string
y=['\bf Flag:','\rm' num2str(x)]; %contents of line 2 along with font styles
str=[str newline y] %Arranging the text in order which we want to see
t = annotation('textbox','string',str) %placing the text in textbox
Please refer to the following documentation links for more information Newline , Annotation[SK1] , Textbox properties.
