As per Sikhi, the message of Gurbani enshrined in Sri Guru Granth Sahib, the answer, in simple words is, that all the components that constitute a human being after physical death, merge back into their source.
Please allow me to quote, from page 885 of Sri Guru Granth Sahib, the verse that supports the above response.
ਪਵਨੈ ਮਹਿ ਪਵਨੁ ਸਮਾਇਆ ॥ ਜੋਤੀ ਮਹਿ ਜੋਤਿ ਰਲਿ ਜਾਇਆ ॥ AGGS 885
Pavnai Meh Pavan Samaya || Joti Meh Jot Ral Jaya ||
ਮਾਟੀ ਮਾਟੀ ਹੋਈ ਏਕ ॥ ਰੋਵਨਹਾਰੇ ਕੀ ਕਵਨ ਟੇਕ ॥੧॥
Mati Mati Hoi Ek || Rovanehare Ki Kavan Tek ||1||
The spirit of the message is: At the (physical) death, the breath merges back into the air, universal energy (Jot) blends back into the larger universal energy (Jot), the body (that got its nourishment from the earth) merges back into the earth, (so) what is base for the lamenting.
The implication is provided in the last line, included below, of the SABD.
ਕਹੁ ਨਾਨਕ ਗੁਰਿ ਭਰਮੁ ਚੁਕਾਇਆ ॥ ਨਾ ਕੋਈ ਮਰੈ ਨ ਆਵੈ ਜਾਇਆ ॥੪॥੧੦॥
Kahu Nanak Gur Bharam Chukaya || Na Koi Marai N Avai Jaya ||4||10||
Guru Nanak clarifies that nothing has died / vanished, or come and gone. meaning that it is only a transformation of one form into the other.
Another verse, from page 846 of Sri Guru Granth Sahib, restates the above:
ਸੂਰਜ ਕਿਰਣਿ ਮਿਲੇ ਜਲ ਕਾ ਜਲੁ ਹੂਆ ਰਾਮ ॥ ਜੋਤੀ ਜੋਤਿ ਰਲੀ ਸੰਪੂਰਨੁ ਥੀਆ ਰਾਮ ॥
sūraj kiran milē jal kā jal hūā rām || jōtī jōt ralī sanpūran thīā rām
The spirit of the message is: That is, as the sun’s rays fall on the ice, it becomes water and merges back into its original source. In the same way, the (Physical) death. Jyot (part of the Creator) merges back into the Creator (Joti) and that completes the objective.
And finally: a verse, from page 1037 of Sri Guru Granth Sahib, that wraps it all up is as follows:
Now this is not about an individual death but for the entire Creation.
ਸੁੰਨਹੁ ਖਾਣੀ ਸੁੰਨਹੁ ਬਾਣੀ ॥ ਸੁੰਨਹੁ ਉਪਜੀ ਸੁੰਨਿ ਸਮਾਣੀ ॥
Sunnahu Khani Sunnahu Bani || Sunnahu Opaji Sunn Samani ||
The spirit of the message is: The source of every life and order is Primal Void and (after death) will merge back into the Primal Void.
Normally such questions arise from beliefs of other faiths. The Gurbani has following to say about them:
ਇਕ ਦਝਹਿ ਇਕ ਦਬੀਅਹਿ ਇਕਨਾ ਕੁਤੇ ਖਾਹਿ ॥ ਇਕਿ ਪਾਣੀ ਵਿਚਿ ਉਸਟੀਅਹਿ ਇਕਿ ਭੀ ਫਿਰਿ ਹਸਣਿ ਪਾਹਿ ॥
ik dajhah ik dabīah ikanā kutē khāh || ik pānī vich usatīah ik bhī phir hasan pāh .
ਨਾਨਕ ਏਵ ਨ ਜਾਪਈ ਕਿਥੈ ਜਾਇ ਸਮਾਹਿ ॥੨॥
nānak ēv n jāpaī kithai jāi samāh .2.
The spirit of the message that some cremate the body, other burry it, some leave it to dogs to eat, some throw it into the water and still others leave it in isolated places.
It doesn’t appear that they know the final destination.
Hope this helps clear the Sikhi view of what happens after (Physical) death.
