Gerald,
If the Makrofile/tiddler containing the macro definition is tagged with $:/tags/Macro then <<Makro>> will be available in any tiddler.
However an alternative is to not define it as a macro but put your code in a tiddler lets call it makrotemplate
then where you want to use it in any tiddler,
`{{||makrotemplate}}` the `||` says use the currentTiddler when transcluding.
As long as a macro - or a template is designed to operate on the currentTiddler it is easy to include it in any tiddler.
I hope this helps without giving too much information
Tony