For most of these online services, SMILES strings are the easiest way to input molecules. The CTRL-ALT-C shortcut should be configured by default to copy SMILES strings in Chemdraw. Nearly every chemical drawing software accepts pasting of SMILES strings.
Columbia's Chemdraw professional license includes a built in feature for simple predictions of proton and carbon NMR however it's pretty rudimentary.
If you've configured the licenses properly Mestrenova should also be able to perform NMR predictions. However, you only have 15 minute windows of access to the license for prediction and cannot use it while someone else is using it. Make sure to save all of your files before and immediately after using the prediction feature as the software will close when your window is up.
NMRium (https://www.nmrium.org/predict) offers prediction for Proton, Carbon, COSY, HSQC, and HMBC. NMRium also offers the ability to import spectra and analyze them directly on the website. Eventually once some licensing is sorted out NMRium should be directly integrated into our ELN instance allowing you to upload and analyze NMR data attached to experiments or specific molecules.
molGPKA (https://xundrug.cn/molgpka) uses neural networks to predict the pKa of every proton on a given molecule.
EsNuEl (https://esnuel.org/) can be used to estimate the nucleophilicity and electrophilicity of different sites on a given molecule. Remember that if you're introducing bases or acids in your reaction you should draw structures in the proper protonation state.
ALFABET (https://bde.ml.nrel.gov/) is a tool that "predicts BDEs for single, noncyclic bonds in neutral organic molecules consisting of C, H, O, and N atoms. Mean absolute errors are typically less than 1 kcal/mol for most compounds."