Mass inserting one piece of information

HI all,

I have a spreadsheet which in column C has many rows 10000+ of written information, I am looking to insert for example one word lets say "Hello" into each of the columns which contact all this written information but just need this word to be placed infront of all the written information but in the same column

example:

Column C, row 1 to 10 has "We have a test" in each row written
and
Column C, row 11 to 20 had "We do not have a test" in each row written

Now so that I do not need to click on each row and add the word "Hello" can I tell it to mass insert the word "Hello" in from of those phrases in each row giving me:
Column C, row 1 to 10 "Hello we have a test"
Column C, row 11-20 "Hello We do not have a test"


I hope this is simple to do and would like to avoid macros if possible.

Thanks.