Hello
Sometimes i want to repit object, drawing, legend in layout.
I simple copy anda past elements.
If i change one and have several copys i have do change all if i remember where 
As i know components don´t exist in layout?!
How clould i resolve the challenge?
Thanks
The idea of having something like components in LayOut has been requested as a feature. We can hope it will happen one day.
Currently you could put the object or drawing ona shared layer. It would then automatically appear on every page for which that layer is visible. Editing it on one page would result in it being edited everywhere else.
For text objects like your legend, you might be able to use custom Auto Text elements and then edit them in Document Setup>Auto Text or you could create the legend as a spreadsheet in Excel or equivalent and insert the .xlsx spreadsheet file into LayOut. You can copy it and paste it as much as you like. Edit it in the spreadsheet application when needed and update the reference.
DaveR Thanks for the tips, some are very relevant, others I was already using.
Let’s hope this feature arrives as soon as possible. Good job