Pausing Macros for User Input

@Adrian
The use of InputBox can be as simple as this:

Sub Test()
Range("A1") = InputBox("Type something")
' if needed, your code goes here
End Sub

If you enter a number, VBA enters it as numeric.
If you type a string, VBA enters it as text.
If you press OK without typing something or press Cancel or Esc, VBA will clear cell A1

@Adrian
I think you want a modeless UserForm. In VBE, use Insert > UserForm. Decorate your UserForm1 (add a Close button), then in your VBA macro, add:
Load UserForm1
UserForm1.Show 0 ' show modeless
Add a While loop with
Application.Wait(Now + TimeValue("0:00:01"))
to monitor the Close button's Click event. While the form is displayed, the macro will pause and you will be able to edit cells. When the form is closed, exit the While loop.

Adrian

Sub tester()
Dim x As Variant, c As Range

x = Application.InputBox("Enter your text", "Something Useful", , Type:=2)
[a2] = x
For Each c In ActiveSheet.UsedRange
If c = [a2] Then
c.Font.Bold = True
End If
Next
End Sub

Of course you do not have to enter x into A2 the macro can just refer directly to x
If c = x then ...

Type 2 is a string, see J Jooleys post below.

I am sorry to appear very thick but I cannot work this out at all, using VBA is it possible to pause a macro to add text into cell a2 then hit return and move on and continue with the macro?

Here is a typical example of the use of InputBox and MsgBox: This macro asks to enter a column letter or letters and gives you the corresponding column number.

Sub ColNr()
X = InputBox("Column letter(s)")
X = Sheet1.Range(X & 1).Column
MsgBox "Column number is: " & X
End Sub

This is a simple macro that does not trap errors.
You can even combine it's 3 lines to one line:

Sub ColNr()
MsgBox "Column number is: " & Sheet1.Range(InputBox("Column letter(s)") & 1).Column
End Sub

By adding On Error Resume Next you trap all errors. You don't get an answer but neither do you get a crash message from vba:

Sub ColNr()
On Error Resume Next
MsgBox "Column number is: " & Sheet1.Range(InputBox("Column letter(s)") & 1).Column
End Sub

Here is something to play with:
Copy the following line to the clipboard:
MsgBox "Column number is: " & Sheet1.Range(InputBox("Column letter(s)") & 1).Column
paste it into the Immediate Window in vba and press enter. Have fun.

@J. Woolley: VERY interesting! I didn't know that form of InputBox, but it is the answer to many, many problems... Thank you!

Application.InputBox is more versatile than VBA.InputBox (which only returns a String). Application.InputBox can return a Range or an array of values. See
https://docs.microsoft.com/en-us/office/vba/api/excel.application.inputbox