The applications are for listed building consent and building warrant approval.
The applications, submitted by project architects LDN Architects, are in preparation for the main building works contract. This contract will be subject to a tender process beginning this spring.
The applications cover the works necessary to restore the Category A Listed building and convert it for use as a new visitor attraction.
The council said that, given potential impacts arising from Brexit and the Covid-19 pandemic, the programme of works for the main tender will not be finalised until completion of the tender process. At present, the proposed works include conservation of the building fabric, accessibility and environmental upgrades and new additions. In addition, the proposed works include a new café space and external viewing terraces.
The transformation of Inverness Castle is supported by £15m investment from the Scottish government and £3m from the UK government i through the city region deal.
Provost of Inverness and area, Cllr Helen Carmichael, said: “The Inverness Castle project is vital to the regeneration of our city centre and the wider tourism economy of the Highland region. It is exciting to see the progress towards the Inverness Castle becoming a ‘must-see’ attraction that will draw visitors to the Highlands.”