For equity issues the company will typically publish a price range announcement which will give potential investors an idea of a lower and higher range value for the overall business. The actual price is then announced once the offer has closed along with the basis of allocation.
New investment trusts, funds and bonds are normally launched with a fixed price; therefore investors will know the price prior to their investment.
An investment trust that is already listed on a stock exchange may issue further shares via a secondary offering, the price of these will normally be set at a slight discount to the prevailing market price at the time of the offer announcement.
Once the shares or bonds are listed on the open market, the share price will rise and fall as with all other shares.