I wanted to know exactly what is d concept of Muttah & Sigah in islam,are they both temporary marriage?I know that when a person has physical needs they opt for Muttah or in travelling when they need Maharam,but is Muttah allowed for even those who are unsure of marrying a person and as the divorce rates have increased in our community as it is difficult to know somebody in a short meeting & then do nikah & later on after u start leaving with that person,u may realize its not working so are they allowed to do muttah first??any source books to read about this.also what are the views of ayt.khameni about the same?also somebody asked me is muttah permissible for someone who just needs a moral & financial support & not physical needs & as they are not prepared for the family life?or is muttah only for that person who intends to marry the same person later?

Yes seegha and muta are same and it is temporary marriage
Yes it is for physical and fir support and help purpose also and making mahram while traveling to avoid the Haram.
Yes one can do mutha before marriage and with same person he/she can get married also but Virgin girl must have permission from her father or guardian