I have roughly 15k in my pension and am 31 years old. I recently left my company and have the option to keep my pension at Bank of Montreal, or transfer it to my Roth IRA, or I can open a traditional IRA and roll it in there. Not sure what the best option would be? Or what good questions I should be asking here?
Transferring to Roth IRA is a taxable event. Your pension distribution will be a taxable income to you, but the qualified distributions from the Roth IRA will be tax free (i.e.: tax free income in retirement, including all the gains).
Rolling over to traditional IRA will not trigger any taxes, but distributions will be taxable (i.e.: you'll pay ordinary income taxes on the money when you withdraw during your retirement).
Leaving in the pension fund will keep your pension benefits. You need to check what these are and how reliable they may be. If it is a defined benefit pension, that may be something worth keeping.