after some research, I found out the following:
1. what is the requirements for applying ?
---> 1. You and your partner have to be 18, in some cases if there is a written statement of the paernts they might give permission of marriage to someone of the age 16 and above.
2. As your partner is Latvian, you will need at least "temporary residence permit in Latvia" .
3. You both have to sign the application and submit it at one of the registry office, you need to represent both a passport or ID at this stage.
4. "A marriage may be solemnised:
- by an official of the registry office in the premises of the registry office,
- by an official of the registry office in another place in which the spouses-to-be ensure circumstances that are suitable and relevant for contracting of the marriage,
- by a priest in the church of the confession to which at least one of the spouses belongs. In addition to the abovementioned formal requirements, each congregation may have in place different rules related to, for example, marriage between representatives of different confessions, belonging of the spouses-to-be to the particular congregation and the necessity to undertake a pre-marital courses. Therefore one has to address the priest of the preferred congregation to learn about the particular rules.
Both in the registry office and in the church the marriage will be solemnised in Latvian, but in exceptional cases and upon a request of the spouses-to-be a foreign language may be used at the ceremony.
For the verification of the application and documents necessary for the contracting of marriage a state fee 14 EUR has to be paid, but one should also take into account the costs of registration of the marriage and organisation of the solemn ceremony. These expenses are set out in the pricelist of the local government in which the registry office operates. If you wish to contract the marriage at the church it may also have a fee for the organisation of the marriage ceremony, but it could also have a custom of covering such costs by a donation of an unspecified amount."
2. can i remain in latvia till the decision or I have to back to home country ?
According to this I couldnt find any information.
3. is there an interview ?
Same as in question 2.
4.am I allowed to work during waiting for decision ?
"The right to work without restrictions is granted to a foreigner who has received an identity document of an asylum seeker and has not received a decision of the Office of Citizenship and Migration Affairs regarding granting refugee or alternative status or a refusal to grant it within 6 months after submission of an application regarding granting refugee or alternative status, and it has not occurred due to his or her fault. The right to work is valid until the day when the final decision regarding granting refugee or alternative status or refusal to grant it has come into force and may not be contested."
As for the questions I could not answer, it might be good if your partner contacts the follwing office in Riga:
Consultations in Riga:
+371 25565098, +371 28612120
+371 67898343 (I - V 9:00 - 20:00)
Lacplesa street 75 - 1 B, Riga
I hope I could of some help.