Encryption-then-encode or encode-then-encryption? I have this question in which I m struggling. I have read in many sites about encrypt-then-mac etc.

If the confidentiality for transmission is needed, discuss the feature for the order of encryption and encode by error correcting code (ECC), i.e., 1) encryption-then-encode, 2) encode-then-encryption.
With some modes you can encode then encrypt, specifically stream cipher modes (CTR, OFB). Bit errors during transmission translate to identical bit errors in the encoded plaintext, and error correction will work as intended.

However, with standard block cipher modes (ECB, CBC), the entire block is encrypted, and a 1 bit error in the ciphertext creates many bit changes to the decrypted block due to the avalanche effect. Depending on the type of correction used, this may be correctable, but it is generally better to apply the code to the ciphertext.