The best way to contact me is Email. To keep our communication confidential, I can offer you different possibilities of encryption:
Pretty Good Privacy (PGP)
The decentralized PGP protocol enabled encrypted communication using public and private keys. The main problem of this protocol is to distribute the public keys while assuring their authenticity. Therefor, you can find my public key not only on the key servers where everyone can public keys without any validation but also here: PGP Public Key.
S/MIME is the centralized counterpart for PGP. The authenticity of the public keys is validated in this protocol by a signature of a trustworthy certificate authorify (CA) that are owned by states and companies. While this solves the problem of the key distribution it makes the confidentiality of the communication dependent from the trust in all certificate authorities, which is why many whistleblowers and other dissidents refrain from using this protocol. To enable you to also use this protocol when sending mails to me, you find my public key here: S/MIME Public Key.
S/MIME is natively supported by many email clients and you can get an own certificate for free, for example from Actalis (as of 07/2019).
Both preceding approaches are trying to secure the email protocol which is insecure by default. A common alternative today are encrypted instant messengers that are easy to use and therefor do not pose the threat of misuse. On the one hand side I want to highlight the Signal messenger, which is developed and operated by the non-profit Signal foundation and whose open-source encryption protocol is universally seen as secure und is used by other messengers as WhatsApp. On the other hand side, though Threema is not open-source nor free it provides another secure method of encryption and follows the privacy regulations because it is located in Switzerland.
In Threema you can find me using the ID CAEVDC65 und in Signal using my mobile phone number which you can ask for if you want to contact me that way.