There are 3 ways to set Text as Bold.
1st way:- Directly write Font-Bold property in Label declaration.Font-Bold has True and False values.
For Example:-
<asp:Label ID="lbl_phone_number" runat="server" Text="1234567890" Font-Bold="true"></asp:Label>
2nd way:- We can assign property at run-time.Label has Font.Bold static property.We can set it to True or False.
<asp:Label ID="lbl_adddress" runat="server" Text="Pune"></asp:Label>
In Code-Behind,
lbl_adddress.Font.Bold = true;
3rd way:- Is the best way to format Label dynamically with <b> tag in starting and ending of Text as shown:-
<asp:Label ID="lbl_name" runat="server" Text=""></asp:Label>
In Code-Behind,
lbl_name.Text = "<b>" + "Vishal" + "</b>";