How can I draw cyclodextrin molecule in avogadro ? is it added in avogadro library ?
There are no cyclodextrins in the default library, no.
One trick is that there is no one “cyclodextrin” - they are a family.
You can grab 2D structures on PubChem: https://pubchem.ncbi.nlm.nih.gov/compound/alpha-CYCLODEXTRIN
If you download the 2D SDF file, Avogadro can start to predict a 3d structure and optimize.