you also have to add a ‘g’ at the end to make replacements ‘global’. By default, sed will just do one replacement per line. With ‘g’ it replaces everything.
Example with some random test file I made:
$ sed 's/Text/Architecture/' test.txt
this is a Architecture on Text where Text
is a very important Architecture.
But Architecture is Text.
$ sed 's/Text/Architecture/g' test.txt
this is a Architecture on Architecture where Architecture
is a very important Architecture.
But Architecture is Architecture.