I am looking to create a macro that will select a line that contains a specific word. Ideally it would select all the occurrences in the whole document at once. The word would always be the same so no need for a prompt. I got started but am not sure if I a headed in the right direction. I am pretty lost when it comes to VBA. Any help would be greatly appreciated.

Sub AdjustText()
'
' AdjustText Macro
'
'
Dim myRange As Range
Set myRange = ActiveDocument.Range


With myRange.Find
.text = "Word"
.Replacement.text = ""
.Forward = True
.Wrap = wdFindContinue
.Format = False
.MatchCase = False
.MatchWholeWord = True
.MatchWildcards = False
.MatchSoundsLike = False
.MatchAllWordForms = False
.Execute
If .Found Then
Selection.Extend
Selection.Extend
Selection.Extend
End If
End With
End Sub

The correct way to encode such a macro (if one is needed at all) depends on what you mean by "select a line that contains a specific word", which is different from your thread title that mentions sentences. Do those lines constitute an entire paragraph? Alternatively, are the lines terminated by manual line breaks? Do you want both ends of the 'line' included? Then there is the question of what you actually want to do with these lines?

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

I am looking to select the entire line. Using the word sentence in the title was misleading.

Yes the lines constitute an entire paragraph.

The lines are terminated by manual line breaks.

I would like both ends of the line included.

Once selected I would be making changes font and other text formatting.

These two statements are inconsistent. Please clarify. With Word's formatting display turned on, are these lines preceded by ¶, or by ↵?
Without knowing what those changes are (which quite possibly should be applied via a paragraph Style, it's impossible to write the required macro, since macros process such content iteratively, not concurrently.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

the line is preceded by ¶. Sorry for the confusion.

I will be changing the font size.

In that case you should create a paragraph Style with the attributes you require and apply that. The Style can be applied quite easily via a wildcard Find/Replace, where:
Find = Word*^13
Replace = ^&
and you specify the Style as a replacement parameter. No macros required.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

I would want to change the font size of the entire line that contains the word. Not just the individual word.

The word document is generated automatically from another program. I have no ability to control the paragraph style or formatting. Just trying to increase the text size of specific lines to be larger and have the whole multi page document done all at once.

As I said, you can do that via a paragraph Style. You clearly didn't try the wildcard Find/Replace I suggested; otherwise you'd know that by now.
It makes no difference what the document's origin is if you add the Style to it via the Organizer.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]